Anal cancer is of growing concern in the United States and elsewhere, particularly among HIV-positive men who have a much higher than normal incidence of this human papillomavirus-associated neoplasia. Standard of care chemoradiotherapy has remained unchanged for decades and is of limited value in treating patients with advanced or recurrent disease. Anal cancer is a poorly understood disease owing to the absence of preclinical models for its study. We have developed the first preclinical animal models for anal cancer. Using these models, we have begun to study the role of viral oncogenes in this cancer. Furthermore, we discovered that the mTOR pathway is highly activated in anal cancer and is a valuable target for treating this cancer. In this grant applicatin we propose experiments using these new preclinical models to understand the role and temporal requirements for individual HPV oncogenes in anal carcinogenesis, and their influences on the responses of anal cancer to chemoradiation. We will also carry out studies to investigate further the value of drugs targeting the mTOR and MEK/ERK pathways in treating anal cancer. Lastly we will investigate if PI3K activation, which is upstream of the MTOR and MEK/ERK pathways, drives anal carcinogenesis together with HPV oncogenes. The studies described in this grant will provide new insights into more effective ways for treating human anal cancer.